Activate the Extrude command and click on the front face of the part geo-
Draw a closed sketch and apply dimensions to it.
On the ribbon, click Home > Sketch > Finish .
On the dialog, select Start > Through All . Under the Boolean section, select
Boolean > Subtract .
If the extrude handle points toward front, then click the Reverse Direction
button under the Direction section.
Click OK to create the cutout throughout the part geometry.